High OA rates reported for US armed forces personnel

Abstract

MedWire News: US military personnel carry a significantly greater burden of osteoarthritis (OA) than the general population, reveals research published in the journal Arthritis and Rheumatism.

"The findings of this study may be applicable to younger individuals with athletic or occupational exposure to joint loading tasks," explain lead author Kenneth Cameron (Keller Army Hospital, West Point, New York) and colleagues.

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The team examined cases of OA diagnosed in active US service personnel between 1999 and 2008 using the Defense Medical Surveillance System, and collated information on age, race, gender, branch of service, and rank.

Overall, 108,266 incidences of OA were identified over 13,768,885 person-years of follow-up, giving an unadjusted rate of 7.86 cases per 1000 person-years. The rate increased from 1.84 cases per 1000 person-years for personnel aged less than 20 years to 26.91 cases per 1000 person-years for those aged over 40 years.

Compared with previously reported data for the US general population, armed forces personnel had significantly higher rates of OA at all ages, with incidence rate ratios (IRRs) of 1.26 and 2.17 for the youngest and oldest personnel, respectively.

Analysis showed that OA was especially common in female versus male personnel (adjusted IIR=1.19), and Black and White personnel versus those of other races (adjusted IIRs=1.26 and 1.10, respectively).

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Compared with navy personnel, those in the army were 1.49 times more likely to have OA, and junior and senior enlisted personnel were significantly more likely to have OA than junior officers (IIRs=1.49 and 1.67, respectively).

Noting that traumatic joint injury is strongly associated with OA development, the researchers comment: "The present study is the largest known population-based study to examine the incidence of OA in a relatively young and physically active population that is at increased risk for traumatic joint injuries; a group which has been understudied in relation to OA."

They conclude: "Due to the high rates of traumatic joint injury within the military population, further research is needed to determine the incidence of post-traumatic OA and to further delineate the risk factors associated with this condition within military populations."